Key information relevant to the recruitment process for the
overall study, such as dates of the recruitment period and locations

A total of 656 participants underwent randomization

participants to endovascular therapy >> and 222 to intravenous t-PA alone) at 58 study >> centers between August 25, 2006, and April 17, >> 2012 in the United States (41 sites), Canada (7), >> Australia (4), and Europe (6)

Pre-Assignment Details

Significant events and approaches for the overall study
following participant enrollment, but prior to group assignment

No text entered.

Reporting Groups

Description

Endovascular Therapy

Endovascular therapy (group two) received a lower dose (0.09mg per kg bolus and 0.54mg/kilogram infusion over 40 minutes, maximum dose 53.6mg) or after Amendment #5, a standard dose of IV rt-PA (.9mg/kg with 10% as a bolus and the remainder over one hour) and then underwent an angiogram test (cerebral angiography) right after the medicine was given to check for blood clots. If a clot was not seen, then no more treatment was given. If a clot was seen, the neurointerventionalist chose (based on the location and extent of the blood clot) a protocol approved endovascular treatment given directly in the brain artery that would be most effective in reopening the blocked artery.

IV Rt-PA Alone

IV rt-PA alone (group one) received the standard dose (.9mg per kilogram with 10% as a bolus and the remainder as an infusion over 1 hour -maximum dose 90mg) of intravenous (IV) rt-PA alone.

Explanation of how the number of participants for analysis was determined.
Includes whether analysis was per protocol, intention to treat, or another method.
Also provides relevant details such as imputation technique, as appropriate.

A sample of 900 was calculated to provide an effect size of 10 percentage points assuming that 40% of the patients had a good outcome in the IV t-PA group, as noted in patients in the NINDS rt-PA Stroke Study who had age and baseline stroke severity similar to the eligibility criteria for the IMS3 trial. The trial was halted at 656 subjects.

Reporting Groups

Description

Endovascular Therapy

Group two will receive a lower dose or a standard dose of IV rt-PA and then undergo an angiogram test (cerebral angiography) right after the medicine is given to check for blood clots. If a clot is not seen then no more treatment will be given. If a clot is seen, the neurointerventionalist will then choose (based on the location and extent of the blood clot) a protocol approved endovascular treatment given directly in the brain artery that will be most effective in reopening the blocked artery.

IV Rt-PA Alone

Group one will receive the standard dose of intravenous (IV) rt-PA alone given over an hour.

Total

Total of all reporting groups

Baseline Measures

Endovascular Therapy

IV Rt-PA Alone

Total

Number of Participants
[units: participants]

434

222

656

Age
[units: years]Median (Full Range)

69
(23 to 89)

68
(23 to 84)

69
(23 to 89)

Gender
[units: participants]

Female

216

100

316

Male

218

122

340

NIHSS Score
[1][units: Score on a scale]Median (Full Range)

17
(7 to 40)

16
(8 to 30)

17
(7 to 40)

Time from stroke onset to initiation of IV rt-PA
[2][units: minutes]Mean (Standard Deviation)

122.4
(33.7)

121.2
(33.8)

122.0
(33.7)

NIHSS Score Strata
[units: participants]

NIHSS Score <20

302

150

452

NIHSS Score > = 20

132

72

204

[1]

The National Institutes of Health Stroke Scale (NIHSS), a serial measure of neurologic deficit, is a 42-point scale that >> quantifies neurologic deficits in 11 categories, with 0 indicating normal function without neurologic deficit and higher

>> scores indicating greater severity of deficit.

[2]

Time from stroke onset to initiation of intravenous (IV) rt-PA in minutes.

Limitations of the study, such as early termination leading to small numbers of participants
analyzed and technical problems with measurement leading to unreliable or uninterpretable data

The IMS III trial was stopped early because of futility, according to the prespecified rules. A limitation of our trial is that it did not compare the efficacy of the new stent retrievers with that of intravenous t-PA alone.